Many different carton blank designs have been devised for producing cartons with reclosable pouring spouts. A primary purpose of these prior constructions is to provide a unitary carton blank which will produce a carton with a reclosable pouring spout without requiring additional spout structure. With prior constructions, however, problems have been encountered in designing a blank capable of producing a carton which can be completely sealed and still permit opening into a spout shape. Complete sealing of the carton is especially desired where the carton is to be used to contain loose, fine, granular material. Any unsealed crevices will permit leakage of the material during handling and shipping. Obviously, this is undesirable both from the standpoint of material loss and appearance of the carton.
Further, with prior cartons constructed with pouring spouts, problems have been encountered with regard to the actual opening and closing of the spout. Desirably, a minimum understanding and manipulation of the spout should be required. Ideally, the appearance of the carton itself should clearly indicate to the consumer, without further instruction, how to open and close the pouring spout.
Prior unitary carton blank constructions designed for producing a carton with a reclosable pouring spout are exemplified by the following patents: Dunning U.S. Pat. No. 2,509,289, Asman, U.S. Pat. No. Re. 25,532, and MacKendrick, U.S. Pat. No. 3,306,514. Each of the above patents disclose carton blanks which are formed with fold and score lines so that in erected position, the carton may be broken along the score lines and fold along certain of the fold lines to provide a pouring spout. The constructions disclosed in the above patents, however, have the disadvantages of the prior art constructions discussed above.
In particular, the cartons of the Asman and MacKendrick patents cannot be completely sealed to prevent leakage of fine granular material; nor is it evident from the appearance of the carton itself how one is to form the pouring spout. Not only will instructions be needed to inform the consumer as to the opening procedure; but care must be taken in properly executing the instructions so as to avoid unwanted ripping of the carton.
In the Dunning patent, the formed carton can be completely sealed prior to the original opening of the pouring spout. However, the carton appearance does not readily advise the consumer as to the opening procedure. In addition, reclosing of the pouring spout cannot be made with assurance that the spout will remain closed.